The dimples on a golf ball play the role of assisting the transition of a boundary layer created in proximity to the ball surface due to motion and rotation of the ball from laminar flow to turbulent flow to move the point of separation rearward, thereby reducing pressure drag and creating a lifting force due to the difference of separation point between upper and lower positions of the ball. The separation point varies as various dimple parameters such as diameter and depth are changed. Thus the flying orbit of a golf ball is determined by a particular setting of dimple parameters.
The dimple parameters are one of the important factors for improving the flying performance of golf balls as described above. A variety of technical proposals have been made in the past for configuring the dimples on golf balls, particularly regarding the dimple distribution pattern and dimple configurations including dimensions such as diameter and depth. For example, U.S. Pat. No. 4,681,323 discloses the cross-sectional shape of dimples, U.S. Pat. No. 4,840,381 discloses the relationship between the cross-sectional shape and volume of dimples, and Japanese Patent Application Kokai No. 51871/1988 discloses the distribution of dimples.
There still exists a demand for further improving the flying performance of golf balls.